What illegal shift? One goes in motion. If it was an illegal shift it would be called. Everyone thinks they understand the double wing and in reality you know nothing about how it works.
Ok... Only been studying it, using it and variances of its blocking schemes for over a decade since I started coaching. And which version do you mean? Markham, Wyatt, Calande, Murphy? There is far more than one way to run a doublewing, just like any other offense.
But you're right. I don't know anything about the doublewing, or single wing, or Rockne Box, or Split T, or Veer. I don't study contrarian schemes at all lol.
As to the illegal shift, both wings are moving before the snap on some plays. And sometimes Central has been called for it this year, most of the time not. Like
@ocdavis31 said, it's like palming the basketball. Rarely gets called.